Overview of Shark Bay

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Overview of Shark Bay

This is a transcript of a QuickTime movie (11.5 MB) recorded at Shark Bay in 2005. Ross Mack, from Conservation and Land Management, Western Australia, gives an overview of the Shark Bay environment.


Shark Bay is a really unique area and as far as I am aware there’s only two or three places in the world that have stromatolites similar to this. Also as far as I am aware we have perhaps the greatest concentration of them that are occurring in the marine environment at the moment. The stromatolites here are distributed all around the shore of Hamelin Pool which is quite a large distance. We haven’t entirely mapped the full extent of them as yet, that's one of the things we are working on. The main feature of Hamelin Pool that makes it a good place for stromatolites to grow is the presence of the Faure Sill which is a large sea grass bank which occurs across the north end of Hamelin Pool and because of the presence of the Sill it actually creates a hyper saline environment in the Hamelin Pool and that actually restricts a lot of the marine fauna and flora that occurs in the area and that prevents animals occurring here that might actually feed on stromatolites and things like that. I guess it makes it more conducive for them to grow in this area. There’s are quite a few different types of stromatolites. The ones we are getting here, the tidal ones, are these club formed ones. The ones we often get in deeper water are more column shaped. They are often quite higher than the club shaped ones. Right in the foreground here we have algal mats which many people believe are the precursors to the actual stromatolite form. So I guess what we are seeing here are the club shapes and algae mats, and perhaps forms that are intermediary as well between those two. What actually makes the stromatolite grow as opposed to just remaining as an algal mat. Why does it suddenly form a club shaped or a column, as opposed to areas that don't. That's one of the things I ask of everyone who comes here and I am not entirely sure of that. A lot of people come here and aren't sure either. Stromatolites we are seeing here are probably developed over the last 2000-3000 years. So how long it actually takes an individual one to grow I am not sure, but the formations we have here we think are about that old. There are different colours that occur on stromatolite, are often linked to their position on the shoreline and the degree to which they are inundated or remain intertidal, or in fact that they might have been stranded by changes in sea level, so the black and the red colours we think are indicative of exposure to UV radiation, in particular the red ones and possibly the oldest may actually be dead. The mats in particular are very fragile and one of our management priorities for the Shark Bay area is to try and preserve them from deliberate or even incidental damage by visitors and for that reason we restrict access to many of the areas around Hamelin Pool that we perceive to be particularly delicate, even though stromatolites look for all intents like rock they are actually pretty fragile and for that reason also we try and keep people away from many areas. We have constructed a boardwalk down at flagpole landing where people can actually view them without having to walk on them.




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